Too Dry to Dry?

As time goes on, the two hams continue to dry, the prosciutto at a faster pace than the molasses ham.

The prosciutto is coated in a thin layer of lard and cheese cloth, while the molasses ham is exposed to the air. The weight loss for each ham has been minimal since they were hung in our temperature and humidity controlled refrigerator 4 weeks ago.

The recipe suggests ideal conditions for ham storage during the drying period of 60% to 70% humidity and 60 degrees F. Our faithful reader Stooxie commented that dry air can cause the skin of the ham to harden, not letting moisture escape.

While doing the water activity testing, I noticed the skin on the molasses ham felt slightly firmer, though the water activity readings continued to lower at a fairly regular rate. After realizing I’d neglected to monitor the humidity on a regular basis, I checked to find that the air in the fridge had gotten down to about 40% humidity. I added a container of sodium chloride solution to the fridge, bring the humidity up to 60% which it has maintained since.

A Google search has lead me to pictures of prosciutto hanging by the femur near the knee socket, the meat drooping like a large tear drop. There is something classy and alluring about these hams. Alternatively, our hams were cut short, through the femur bone, making them boxy rather than tear dropped. They are hung by string as shown below.

As I approach the fridge, my senses are delighted by the aroma of smoked hickory. And, after feeling the moist, smooth, and leathery skin of the molasses ham, my finger tips continue to hold onto its inviting scent. Though I did let the humidity in the fridge drop for a time, I’m confident the hams are still in good shape and will dry as expected.

6 Comments

I’m honored by the mention! Yes, the ham skin will rehydrate with the increased humidity. This is, in fact, necessary if you want any hope of cutting the skin off at some point. I will let the hams dry at 70% humidity for a year or so then bring them into a “normal” part of my basement (40-50% humidity) to essentially halt the drying process by letting the skin harden. The meat is still aging in side and drying ever so slowly. When I want to slice up the prosciutto (after about another year) I will place the ham back into 70% humidity and the skin will soften again. At that point I can flay it off with a sharp knife.

Of course water cannot penetrate the lard so that is always an impermeable barrier. Water, however, CAN conduct through the ham’s natural fat since the cells are in tact and water can flow around them towards the outside. That’s why the hams take so long to dry, they are drying very slowly through the skin, and that’s why it’s important to keep that skin leathery and not hard.

If you want to see what I’ve done look at the Facebook group “The Swinesmith”.

I sort of got fixated in the specifics of the ham and missed a broader point. Your title of “Too dry to dry” is an excellent point. This is absolutely true with any dry cured product and one of the seeming paradoxes of the art. Water movement is all about osmotic potentials, capillarity and permeability. If you have a sausage or ham in an environment that is too dry the outside skin or casing just hardens into a rock and traps the rest of the moisture inside. You want to “wick” the water out slowly by creating the right potential in the atmosphere. Hence the call for high humidity, sometimes shockingly high like 85% to 90% rh.

If you have the right conditions and keep the humidity about 5% below the Aw as it dries you can actually get results quite quickly. About 3 weeks is all you need to dry a salami or bresoala to 35% of it’s original weight. Of course sometimes you want it to take longer to give the good bacteria a little more time to work it’s magic!

Thanks Stooxie for all of your great insights. I checked out your facebook page – the pics of your cured meats look great. We’re novices at this still, so I appreciate your expertise. One question I have is, How do you control the humidity? We’ve just been adding pans of water or salt water to the fridge, but as you’ve noticed, we haven’t always had the best of luck maintaining the desired humidity. Is there a better, preferably inexpensive, way? And, when curing sausages and salami, can you have higher humidity without growing bad mold?

As far as testing water activity and moisture movement, our company is full of expertise, but not me specifically. We know that water moves from high potential to low. It’s interesting to learn that having ambient conditions that are close to the same potential, but slightly lower will move the water from the meat more quickly. When I water my garden using a sprayer on the end of the hose, rather than using a sprinkler or soaker hose, a lot of water hits the dry earth in a short amount of time. As a result, there is a lot of runoff and I wonder how deep I’ve actually watered. I’m thinking that if the soil – or edges of meat – already contain plenty of water molecules, the water moves more freely from point A to point B. By keeping things moist, we build a water molecule highway rather than a roadblock.

Let me first say that I wish there was a blog like this when I started out as it would have save me a LOT of trial and error! So I am sharing what I know so that others can get a head start.

The single best way to achieve proper humidity and temperature control is to do what we’ve been doing for 100s of years: cure meat at the right time! If you hang a big pile of meat in a crawl space or fairly close basement in the cool fall months everything pretty much happens automatically. Freshly hung meats/salamis will put out enough water to keep the humidity around 85 to 90% and that will drop off slowly with a bit of airflow, and even from what concrete blocks or stone will absorb.

Beyond that, the farther we get away from nature’s cycle the more we have to interfere. I developed a method for controlling humidity that essentially runs itself indefinitely. If you give me an email address I’ll send you pictures but here’s the gist. You need a water source like a hose bib. I had one installed in my drying room. Then you take a hose thread to 1/4 adapter and use an ice maker hose to connect it to an inline filter. Then another ice maker hose connects it to a mini ball valve that it on the inside of a plastic container. Now you have a plastic container that will always stay filled with a certain level of water. Yup, like a toilet tank! Then you drop in a fountain mister and plug that in to a humidity controller. I use the NIST traceable 4190 controller from VWR.com. I paid about $106 for it. Have a fan blowing fairly low towards the container so any mist is dispersed. Air movement is good for curing anyway so that will serve double duty. So that’s basically it. Just set the humidity controller and it runs itself as long as you like.

Finally, just for good measure, I have a second humidity controller attached to a DEhumidifier with a drain line in case the humidity goes up too high. That happens all the time when fresh sausages are hung. They lose about 50-100mL of water each per day so there’s a lot going into the immediate atmosphere!

Controlling temperature is much trickier but I also find temperature to be a far less important factor. Yes, using a fridge as the drying chamber is the easy way but that isn’t enough room for me. I’ve toyed with the idea of installing a mini split system air conditioner but they will remove all the moisture from the room. The next best thing is a wine cooling unit since they are designed to put the moisture back in but now you’re talking thousands of dollars. In the cold months, that’s easy, you just stick any decent digitally controlled electric heater in there.

So, being in northern VA, I can cure comfortably 6-8 months out of the year without worrying about temperature and the humidity setup takes care of the rest.

Regarding mold growth, you can either increase the pH of the casing to retard mold growth, either by smoking (best) or using vinegar (pain in the rump). Otherwise inoculating with penicillin is the easiest way. Just culture your own good mold and the bad molds can’t compete. Even the huge producers like Columbus will inoculate everything. The casings are then removed and they are re-wrapped for shipment. That’s why it never looks like there is any mold on them.

Hey there just wanted to give you a brief heads up and let you know a few of the images aren’t loading correctly. I’m not sure why but I think its a linking issue. I’ve tried it in two different browsers and both show the same results.